SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd9c92028c3e3daa45b5faa0122be78da78dfc3460c1a2ebd8b4c60de1ace0352' 
  AND token = 'gAhQY9TDmFH1oNfEjAAbebDzpbT0A+7e9ab+aSVdJdQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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