SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd70442594903364ee00ca0e65279a96bdc1136cc40316bd850228fd789a34c9' 
  AND token = 'zs6VJRC/+kVr3xV/NYFfbBKkDL2lqlgcKQMR/t8tgN0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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