SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '861e2c234edcb4b8d8f3abf0e926ba61959b0a547a2dd8ff6b12d9ba34ff596c' 
  AND token = '7j/87sjyRtbg2fGnU58pyQBBhzpDQJ6TgaEC8KAZgKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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