SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a2eb28bfd579199dd325332d608f27b24f07c4171f8e021b9f943ea71919fb8' 
  AND token = 'U5Ygh6KrLNQ73wNY1Mi4HAzVXxuWEViMdHOP/TBfnSM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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