SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31edab64b753af83d0793bc4356b1fedc9c2083f72e7dfafe28d759c244b6dfc' 
  AND token = 'SEs+XXhlm1YPqvqCUiAiwSLFcgTohNZlzN5XpMEVbzU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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