SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '236ddb40c31c19c550e0d8e5f2812d2e6c5c649985bd5ae012889b8bea4c7490' 
  AND token = 'FOmbq7xYzm9rvrphBVfFbdubXUB+Ld9piZ/B1nM4CjE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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