SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb1d035f8a8bad1c3c7c54f40c9fc647465a8aa27c2fb3719c9233868150b800' 
  AND token = 'utXbUvwEwWob1IqVjmi1KFINCYmJd+AWNVSgGJKw9cs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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