SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a1db336bac7f5c242f3881bca3103d462c9b5e7b84c0f938b5700c0841aa4f4' 
  AND token = 'h4uH6dcXUKzOGcK3Be4TuEIykkIRA63AytVAU4kPSWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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