SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '200237b6444fced0e5b6a2a2bddb04c20990668f5e1eefe368b7270cbb691339' 
  AND token = 'tmKFPMXvhzwSit3RBI/3tuKYGIgk0Q81tiJEiP6WI4I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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