SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b5700914193a1a022ff0217e355d51e46934431062d897671cd1071b3f4733f9' 
  AND token = 'i/CrLwi5Uj9628ZfuRTXpl9xxMJ64wH1dT6jn5caRt4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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