SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a658ff4fe818fe205fb1650f96ff7b5e8593f780d0860688b4711056f1bce583' 
  AND token = 'KbSBPKyzMBk364TRab9k3TczLbnG5SyUSuuVuHCNWgI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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