SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3de349e48fb34d47a5690a19648150abc07dc4b5bd9d32d0a4bc65ec9c69f04b' 
  AND token = 'R5yK+2yZbWhUAmV3Xxe1STmA35Pl4y7xuMwO5cu4xkA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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