SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5b8d77d704d3ac9e53ee696f8c48f5e5abdfda0a6f57fa0852e5b3ea186e716' 
  AND token = 'FoZEEObpWq4BcHQWvYauZGjTYXjWFPH7dQwvV3idy5E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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