SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e38574db552e82d11625363aeb8dcd91cf7e8694984f52ae4e1f0fc1737f3f09' 
  AND token = 'xzHagyF7Z2WwXWrPejFZAJw0b+NWpo/WgWqcRbp09KQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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