SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2fe3c0d243773f742e257042557205ad17b67d7d2abba84f826c4686e3ca1b6' 
  AND token = 'p9vBo3/UfVAkX6VQ3U/tVjk8GejuSwQLYQKRZkcveEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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