SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9dcd605b4c50f2b71bb63707a4aaef70296d5c28a87cdcd173bd6925645fbc05' 
  AND token = '6AhtkVpqmsuiNv43t+CRq/cu14TkoDfmuSL+2KXraRo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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