SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4dbb8137e8ebe2137371569d1691c97605f5602f6ef5f11cfb2f273af76749b' 
  AND token = 'SP0zm78NPOsWoCYFHKhfzwQOgDMGpGXRVYJSb+72ZiA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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