SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af0ca66628f71a0d91055a185c1f3425126e1d046d85aa095f64de10a71a65ef' 
  AND token = 'sDFqdezppu/bkoFvGjpbPI3IohplJepyEHEcsuUDNTs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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