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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83d07013463e2caf2a937ad5e7d44f1f5883b7e872ae12a96c3582dbd9b91211' 
  AND token = 'lqo6jbWzZS2l/cLiXqIYdBHm7ZJaSPSuyokQ1tQ1wRI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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