SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff6262d212425396f5c93bd3315ce84ac3e4f0d65cde278d384b38ff70fcdd43' 
  AND token = 'EYHhkl2j/STi8f0wKLLTVWBPjlBZhj7DzRKAp5O7JFI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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