SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d481a6dcab0eec067eebfe1b868fce1b015d9e6d53cf7a33fed22813f1f52cb' 
  AND token = '61RVorCGZox8/UuEAQosCR/PmyuARMnYZGnto8xGDaw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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