SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03b83143c00f81a242d2d53ec012ad33f1582c6c7f396c8b4b76fc677fd39cd3' 
  AND token = 'P4DXVIFebAfVt8ny9ReRWtKFN4HIgzDQj0IQq/TXabY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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