SELECT 
  1 
FROM 
  q_lock_keys 
WHERE 
  key_id = '3884b431b0e236207d41bacb1fb0d52d7f9eefe10d42cdde2e943f976593717f' 
  AND token = '6ZQR8NI+spLWgM6fBbvwPnLl0mswWbzz8rwjJlYm5GU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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