SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '604823fdc85d352f0273465a1ccd1864e65434e51bd2be57fab2db9e8b4b8ddc' 
  AND token = 'lOZj+TjCx+k06ptoIfzCje/ZnaB+bLMg50yUiSPmsBI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}