SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e4fa9ad8496dffb0350000e75d9869c67e551cabb7b56ee4f666dd924f6cb2c' 
  AND token = '2P0aj2/fFTSHqQkWzQeH03wwIFdn+m77P/3tI/lXa5o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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