SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'bedc6115a8b8efe625d9b6307be73f8514c0280024e66929109e45556cb38c5c' 
  AND token = '0RUrrkU3cXkBMOwZw47bKp6QCLXQROcEVREE4jxYV5o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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