SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7be9355f18e2ff02ec75317cf402a58634acfc643820419bb14d992d5988a8b0' 
  AND token = 'DtIFQ1A0QdqS1NIvOGgPsZXm+Vsu6iTrw7pTKIp5PNc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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