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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5b9f63a7d6ff76c0b5caaa86a3e3d6b8d424958ac3aefb6073af079366ca64b' 
  AND token = 'zs4vyZROsSPeWIPQT9ZZ0IMC9fgqNDSI20lE8AUsq7c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}