SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3149ed4ada00382196cbc81a4bb695a637134dc5eb70e4bc9ba04b491f672b49' 
  AND token = 'SsSdb7EPBrRj6awkbZCP+pjhrzAJnnPTAgUl53MutNI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}