SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df912077a601ef03aa7571c1f157cf723a828cc76dda689a687a502ba294417b' 
  AND token = 'djvbb5zawOTTu/CF14eGWF7EtJxe29KDZaqE3gpnUg4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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