SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '39885f2175919f408f2b758b5dea556ff72926d43602140521a5426f2ecc255d' 
  AND token = 'U0GHD0vl3Kg4r6S0nUdVGzubNdvdMZSpBtNaxeOpf/4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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