SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6635a4f54f8c06d5e55d6d4a1c2b74171cf9b5992620d9b1f32aefa0427a19d' 
  AND token = 'I+ozbBInU3jGGj37l5HulIEVG17bOq+hoWVsCd/zZ+A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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