SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fbfc444a4c03ec4c4ac7b72e07ae8516dd83352fe86ca89930a8e337b75a9a0' 
  AND token = 'waTGHEIw4kr8SIrO1+x0eny34fNwKmMp9JTo8FRu6gA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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