SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0392487e60e9383b3c690bea0ee53df1bf10b128bfe53a159d664270eac4099' 
  AND token = 'dKwqAF8d3OelwGWODnq1XY5SQN9ySGxiawZKQmOOAwk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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