SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1453b03e275865b809253c1b4f4b394b4c349ed87b7053e76692155af6318d06' 
  AND token = 'u3qimgn3o809sxE2hADn9+iMoOZSl4dpPJiXygDrpPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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