SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a933f984124d520bb8936c0d8323e5710df04736775b01ce85e7620c4392cd88' 
  AND token = 'X9qTncNuTqaNvIvOyTzDfdNqp2bCNu873M1TUA4WrF0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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