SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e423488c649fd49172e55b7d8070b7f0ca027b9f573caf463e5110f0d37d39d5' 
  AND token = '5DI3gUykTmF/wlGawNOs7jidKk6ofQJAn+mmqnKhcno=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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