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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23d248c3cda5cb30039aa2ba03d57eb3cb0539f41457a922eb59e34a0384e3bb' 
  AND token = 'V41WEFIdLQ9yazjgfhBpLjwB2Kj/ipmK4zHN0yqxt0A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}