SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '019b57fcd2dbf1a5873713a788ce8c2903aa46807bbb892efdeeb9344a73b52d' 
  AND token = 'iD+Gsk/QTQhurcrHAbLrcHKQhfhm88Xg4nHxQSgt03k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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