SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f20e43a0f6f7f975ba8fa0f0be4cb334c5845107dc7cf40d9a25d185c3c373c0' 
  AND token = 'G5u0PCK9wfd4I5OWgNVZOgeo72f/0GxAXhNKQ7ze9nk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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