SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2c151c678c5c5937455d9c9553f9972f72378a3623b10dea45e7fb3031b0b2e' 
  AND token = 'Y4hCjz9rOP+B7vi0jj2I21zTIYKZtfw+4n7Gn1NKP/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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