SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8bdc90d7be6bbefedd45132d01221d502f230a36e7c868ece61a24123e84592' 
  AND token = '/gpDpgFchrultAAPT60KXs8YxFAYFaEkR5hAgSoTM9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}