SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41776f90f8b67ddb3ff97a0b9328f9c2bd39443a500e845f081397797502f1ba' 
  AND token = '+mtHdFOz1uc7q+jI/4vIj9+VyFVNLNAUhZql1VIfbg4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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