SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4ffb8c4d9da4bc5e8a37eac5390d02ff3fcef44a82558c40e3439ff10ae5f56' 
  AND token = 'WoRrPYbzWG7FfBMC0+lEChuTSAwFns9HG0Rkm/zieLw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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