SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f24604e1408765fb7eb59dffe15bb421b609fce4e391187f0ac181c6596c0814' 
  AND token = '0u7ibCWsM8hftPEQYlvXiI3f8MfI7FuajpRlKg/SOyY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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