SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e73618684d52d41f21c498a09612d98ccd4969b32185a5cacfc7d0058f53131' 
  AND token = '0xEHUCLajdtd/Ay6hMfTlwli1MYOTxnhU+2enqmrjgg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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