SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7315a89049a478703fb5033ce77502bafffa3adba76ea9206abe97bae32e97db' 
  AND token = '93kK3a6OUQYP79e08ReiXcSpf2YxaP0VNFSRnSBFPPo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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