SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5b4853d28d110db8ed24810f574d80c9bd9e8672ce2472c9259f6f0ccab2763' 
  AND token = 'HfAGzo+fvL8mE6qNlnyTD5tsPJyTPBdJh2VXQ7LG0wc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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