SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4980c150252230fce2baf43579035206cf1e003f4314b447034a6c24b37436e5' 
  AND token = 'smVS84huoZkZHtj2GFCi/BDBd7ELTvIGOpdKI5goYF8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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