SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1857adf7c5775054c6facfd77e993e7d8eb07d2999c18522669546cf6ecfd462' 
  AND token = 'sL9aQcB+xnM9OYEqPgXWRl8rR5y4o2OMWSHbmFFgJlY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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