SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5faea5dedb53ab4fb8241217a88560f1a15f77402794110af23c81b56183dc2' 
  AND token = 'H96HgDiIK923pFLlvEiFKzrEoqZEzH1hPVaMhpDh53s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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