SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0d40bbffd7ad0fd0e6b659b314260b41864011a8c0f7239c5fae69ddc9d2e6b' 
  AND token = 'UBp+wvCERRvoaEhjFtFVrcii9q/7adjiigpEgfxrxtM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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