SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9bc3009cc041e2ad51d1d91a6f1708a1970c8e77a698edd5c3369ab81fcc64b' 
  AND token = 'BXaMFfrTRghYjGQ34+HwCz3RmgAfPzfKisF3nkvi758=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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