SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54d347812d47d03ecd5d0565b89e3f00a9f57101ae27039bb037f3e27b6b8e2c' 
  AND token = 'ySlFh6YNr/AP/wCujgV8r+Ls9JNJ0mgX8Vy0iIb0GbY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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