SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c760dc52d261b2adfe9bf8be73fa4a9473e7e8e557e6064358e5779a1de356f' 
  AND token = 'nf5xBH5MWbUSTA/LqZ+gLOivnJO1HGopICnvUyrRibw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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