SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4fa726020e033d9cadf62c0d15cb05a410198159c087f387eea2303731784eb' 
  AND token = 'hL22BndVPcu19sbM37MB6yrc8PqhPjwRW+4uhxPec2Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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