SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36692de40753e51be29a2a623ea037f6009abd6433545765ce173a38e3c7d949' 
  AND token = 'fu0PvJmV28y/gONk+vdYEhV4DP1OulKArewjRGKVfHc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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