SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a33d474afec603e08bb0260ec357229f3ef061664c0bae1d33fe3d63b77556d4' 
  AND token = 'CM5y+LRjmA+29jsBpx5av9IgNASIJRebjsiD1NsMXWY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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