SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b936da87a8e739618ec4083c8b7fd6e2fa24e1dd8337f463e3aa7d0259c1c469' 
  AND token = 'x9tyI3o/PyPS0Gfsn4gJRQgzlu9EKNfIp2ZI5KomCV4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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