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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2d4d5341df230372636b8ef49a80f4505f6c8fe70a2dc6cd497fcee1e9c3ffc' 
  AND token = 'dKCNjFliVIc2nK3ISGb5w8cR0iu4AEiKzUw5GVjf7hQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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