SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9bea82898186e2b34d243fdefdc9994123f800deeba727c5e382599ccad17188' 
  AND token = 'JWQejrc+34vmkaCD4lDH90tcJgK3e3ezwYz08OVaKiI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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