SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5996a717926431f88accd522b2b1d0b41f070cc827874f3dc411339792e22d29' 
  AND token = '10Z+HEEEsS0fwQYF4NoCgNyOjoQc07UD/PVoXygIs6Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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