SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11790124482ced26c30637e721043aed70b8dc156b5d4876d4325d15715664ae' 
  AND token = 'TQIr0NOPfcdS8495EfsyhhhOO+I4p5DIuRek+rOzDaQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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