SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f76d4be172201909783184b54e5a887dcdb560fb25c42424b92a7d2f7ba92495' 
  AND token = 'O4yegBCHeObPQog3y0lRmVjjSL6dj4CGPDlAJr5rZ90=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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