SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c134c2b2647233266609c83f97951303af7cd0e00bfe12620aaed65c7f8cf241' 
  AND token = 'I0vHL32reRL8tYwh4QowD5PdYjbbJhKCrCIvIS4HIjw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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