SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99ed6c815f9622fa3cea537ce433802b48b1c5ae2546933971d09672cb1eacaa' 
  AND token = '8DXhs42elQtPT7XGq69V+Js4sumDyqcRKWFaxfxQrbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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