SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a40c5c5434cc9e794c65bb4e4ff95c40016fdc78a47d60375b67050918fb75b1' 
  AND token = 'jAR0/zEuorVbssXGkpYp8tsvckB1wuXo8ZR3JxWUeQA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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