SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75cf082f69d6ed7c72195db24397ea9f902bd4bed083fa82bad981f6f9ce1f6d' 
  AND token = 'bIBtVsXRQ8p95nQNZkoWkwYR7tK4Lw3UyIQ+vCwNrSU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}