SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c32eedffb1475023c84ed84465109dc8e8d0ddd022be09865a0752c8cac4e60' 
  AND token = '4U/HvHt3oATqUMW4bbHzJjuVW0J7nGZqWIDn7XRWjKo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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