SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4ac7231d46bf45fb6d3ed3603e3682794866cbda4b11a77772814881c00be5c' 
  AND token = 'eGSm/TdwcKpS69frzefpjsojUZFBKKRBY5HEXVihcp4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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