SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c3ce931d796939ce33e8b7897c8fa5f71abc415a364f43da8156cc24ee7d7f0' 
  AND token = 'y1i94h5HUJZI8VjLYxH+Bfw/vjZ7JbBt6+e0wzR/jTc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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