SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7589331ed1b39fff18fd2da98063fdfb8676e0fd94ab2fe1f693fcfa5cf2447' 
  AND token = 'cfOVGyuuYgfOiqV9N4l+PLfGyEadjycls9wPLPuNvWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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