SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b64acf92e48e5aa541986cfe8e0e4fcec0abaf78c1203671ee9472e63835c661' 
  AND token = 'ymkvAZczvqGtfo1D6auNNjBmsDhUev6noPM8cCxRSis=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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