SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef9272df934cc2385e9f267e183148a7a67fa198bf2416215ed1bebae859f181' 
  AND token = '/PQSdqrsNUBbJMVaY4cvLocLnBF7RPkwhRujzRc87ok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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