SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'a8f717caad60ad31c8bb1790fbbf326445f10c30834e9ec63f79802c8a44e3d4' 
  AND token = 'aA4KlLJqIIg9JwV8bicZO+VbIlEVXjkAjSCS69OH7dY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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