SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5238adf14ef4fcf97f95e294584716bdf58103b254164f59cc8c3e3d026470da' 
  AND token = 'F5t0lwiZSUeUFS8fN7cY6rk3nh7I5+Z/c19mh2jRqq0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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