SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ac2c35a939796482caddcc390378a2a72f48272014adc7cb9da6889fd944558' 
  AND token = 'Hvb96Dqh0Z2Ue2aC458SQ5uwqWek4E2kKrXhhcEddAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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