SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb00d03037c6f659b28fb54da32fbd3682e83fc287dd4b14e8d6ae5fc79dd961' 
  AND token = '50dN+bYUg22J7UrsdkitYzG3ETjTIYxRbW+JBdMVyu8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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