SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '026bf230b8dd97f7b146bcb2dcd6723143713c815ea22920b8f1681300efdcab' 
  AND token = 'ub6z30z6WlImtSgNa6dieBmdjE5cIAjBaLcZOnDGT8M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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