SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b3981d1aff1ea170ff62840d77fcaccb55c81bda178a72cebca94e98ff5f16d' 
  AND token = 'FpGfqLua/27xA4bkKNS++TGL6gQtqaSbq93N4xkIPVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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