SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df8885cb2c06dc381c9471a98fc14004e7b9d6d25d1d6a3192628693f7822b07' 
  AND token = 'jBdAXT2vtiUedmDchkax+IhsqLHKJbMcAHbIxR/3pnE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}