SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd92a130d8959535270dab13bcbc1de662fd1b76afa6db5de9df0749e299b91e6' 
  AND token = '8MvCsKMsiPvgyR5OpFiBY2T54LmQeH5FcueTCGnRC18=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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