SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28c9444e73fa442693b4aec3c228399afa0bff33330757ccec8769329f5c54c2' 
  AND token = 'BQKURZKPCW+AFGvdDwV/fhD8jOoTKJD+snTax7zluhg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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