SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '917188ef7fe956490af8de5c6043c76da32f96cfafe70b3939a36154a919075a' 
  AND token = 'aq7uEyYLTCJ+c8A4Bs//jH/KYZQj+El8gmFbfk/p/RQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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