SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efaab627defd8ae906e5ce0d6af4e26d25ebd746af431468a4e7291ce0a8947a' 
  AND token = 'FgX3ZpevoDuY+uNWEDXb6v4LmC3MJ3sMU76EVRFg+oQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00061

JSON explain

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