SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6906b319dcbdaa40fb399f6e64598cdde4da693741d69ad7a684aee917ed5e17' 
  AND token = 'PftOSVL3/xAT++iUDRuc//BwmtcTtRKxD2qb0cMSkIM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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