SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b2b10a2a8af14ea52e84bf3369c7d3f7c16a67884a12e6771fdc01f65adf069' 
  AND token = '0Crg1AdI6E2CqPl9DMMNfYFdh8FxFCn4/sV2lmdL84g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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