SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b38f8d8256fc2bc321d48f88d596803db246cb4f0cd2f6173e352b468550db1' 
  AND token = '+ShheeM+dAWliWo0bpa0JA5f+oJ5ziuzhVQMl70x6O8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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