SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbf249fbf2556121b7bea372f2a29176846d208f3b64f4f3009c43bdaa824b45' 
  AND token = 'ue/1ZTm6F5SvFHVrngolsKKn4Nc/II+ezupBsouBm2A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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