SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03155ec6278215cd2589dc0fa2057b4887d8afda3f7f6e05e43c8a9d998c362a' 
  AND token = 'uOcuB7+sYJZK4ciWBMLb9CEsCGjCs4I6qfZTzNjXZOM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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