SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '5336c5ef83d28258f16740a5028f3a669322f99c4b8e318c632d6132b722c324' 
  AND token = '+zSF6XwRLiZOAItPKZqk9mZAWIjj0PRJQ2VM9RQuD9Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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