SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e37f30a66f25884fe95e78011fe164854034612ef01ed031e87d41d2dba6abdd' 
  AND token = '6DWjAyVMq3qn/DsajG+SBLkAuepQg+AkShKhz24/z7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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