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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc0d7b9d2c9b3c69fab7a07b26f25297c826060362f2ff34e3f420d83f91ecc0' 
  AND token = 'OAm/p8/ZTHL+Ba7AbCnmAtyJlayJ6grQ9wJU6/MRgT8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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