SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '356ca830bda611e1a8bd30881d0c28bf826b7a23f82001f6bda6fc404632ad20' 
  AND token = 'XU31Oaa/Sa94VPEmtLVmdWCh4LnyfMFsOhiG7guyPxs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00079

JSON explain

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