SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3233c73c2f000d0e13a49d77da648e24e620a0f90c91a775a26f2c7192b4b0c' 
  AND token = 'vpYgvzWRe4/tjgxNBCJs9m65ceNlh8j/SJKxPVDBLCQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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