SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec6cd75f23ec4dc8146c8eaa55432972081878cf7c5ffbccd916d001f84f6b86' 
  AND token = 'sLYeTVomCCCtgLjtUjJVTABvsKkpqiMKRFWkkUoF8R0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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