SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e28f93a5536faf4238565b451e0fe3a800cfa36975160a153a0fe57ecf9e802' 
  AND token = 'EYSCSP3e680gmFuwyywwksQZkXeyA6KXGGNCMBmdhaw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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