SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d4a132fd36d36c219116aeac0d84d71a54fad3c7a972a364ecdb59eb6e2456d' 
  AND token = 'Lqt+XwBXnO4SVGABBnNGBjBYZf/FpU7pDwy4uVoVh+4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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