SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f407a2dfbb03c53883868656fb88807b21e9cb3efa95367162743eb36751b391' 
  AND token = 'rrjn9lLv2pAQr3v8Y+KKxWIQJDSy48hYvt8STh4GM8U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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