SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83b79ab93f45505158f2e229c391aa298905917c699819e84e22042c00fd5aab' 
  AND token = 'rqasdaVSIVblZvyvsIMbXwhh8suRwt8XIzrAu12PgEQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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