SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eefa5ea50f95eac6d6a90847900d160852b947a4f67c518ca5ad2e7e88cc47fc' 
  AND token = 'FfcwvVaB/inXT/SqOhQ89zCfjEWlVqmtjfNEvCYjet8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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