SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd12d6c71bf966479316f06c894e1bce8ab7d81dfabc1c152e4987afaec4ed47e' 
  AND token = 'oDA/H0O9LFU25mKDrw3qdjSucoHXWJMscFnBDuZJv+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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