SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '598e8e227ebf51002daeed13bba3643f366b162f556991a5e78559994e622e44' 
  AND token = 'kj+VrRVH4a+5E4UImxSFe2OdF9ZxF9R33nY+OMfGCrg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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