SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a58cff88e7de7fc28a06b862a40735f2f1b537b030f0505a69bc5c930b54539' 
  AND token = 'zAq1MhJ0S7yWXXiKJQwx3FWrb8WjzRXyM0SyIPKikLw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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