SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1076641a93becf234217353b095f7e30e44e44d6d6a64a2cb810dde2691eac4' 
  AND token = 'SdoyZx15ZE+fkot5i5BXutP3utbuR51LXGM+rwTOEBc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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