SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8cb8a12bc3fdfe0cd24dfbf2cf71405d08f0d294ad5eb1b05ccc5419046be03' 
  AND token = 'G5a3XqzOAcFKBkSY4S7KMr/5puy2ofArR14Xbq2YJ0s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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